Electromotive-force regulation.



No. 644,864. Patented Mar. 6, I900.

B. G. LAMME.

ELECTBOMOTIVE FORCE REGULATION.

- (Application file d on. 6, 1898.)

(No Model.)-

WITNESSES: m vnvron THE Noam! Pzrzns co, Pumouma. WASKINGTON, o c.

UNITED STATES BENJAMIN G. LAMME, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TOTHE WESTINGHOUSE ELECTRIC AND OF PENNSYLVANIA.

MANUFACTURING COMPANY,

ELECTROMOTlVE-FORCE REGULATION.

SPECIFICATION forming part of Letters Patent No. 644,864, dated March 6,1900.

Application filed October 6, 1898. Serial No. 6925797. (No model.)

[0 all whom it may concern.-

Be it known that I, BENJAMIN G. LAMME, a citizen of the UnitedStates,residing in Pittsburg, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement inElectromotive-Force Regulation, (Case No. 793,) of which the followingis a specification.

My invention relates to electromotive-forceregulation; and it has forits object to provide an efficient means for use'in connection with agenerator that is liable to supply a variable line electromotive forceby reason of variable speed or otherwise in order to secure anapproximately constant line electromotive force.

It is well known that the satisfactory operation of translating devicesin parallel demands an. approximately constant line electromotive forceor one that increases to a limited degree with an increase of load inorder to overcome the'drop in the line. It is therefore generallyconsidered necessary to operate the generator or generators at constantspeed or at a speed as nearly constant as may be secured by properregulation of the prime mover. Where the prime mover is a steam or gasengine, such regulation may be approximated under ordinary conditions,but where awatenwheel is employed for driving the generator theregulation necessary for securing constant speed of the generator iseither impossible or is approximated only with great difficulty andunder the most favorable conditions.

In View of the difficulties attending the attempted speed regulation ofthe main generin speed or in accordance with such other vari-' ations astend to make the line electromotive force variable. In order to effectthis regulation, I have devised the apparatus illustrated in theaccompanying drawings, in which- Figure 1 is a diagram of the machinesand .windin g 3, this being the preferred form, al-

though the series winding may be omitted, if desired. The conditions mayalso be such as to make it feasible to separately excite thefield-magnet, either in whole or in part. I

have shown a variable resistance 4 in the shunt circuit in order thatsuch circuit may be primarily adjusted for the conditions of operationin any given system, but no adjustment of this resistance iscontemplated or will ordinarily be necessary for the purpose of securingthe desired regulation after it has been primarily adjusted for theparticular system in which the machine is to be utilized.

The line-circuit 5 6, supplied by the generator 1, may be utilized forthe operation of any translating devices adapted to the line voltage. Ihave shown lamps 7 and motors S as indicative of such translatingdevices.

9 is a small motor connected across the circuit 5 6 and provided with ashunt field-magnet winding 10. This type of windingis shown asindicative of what is believed to be the pie ferred form, although it isnot desired or intended to limit the invention to this particular formof motor, a series winding,a compound winding, and a separatelyexcitedwinding being within the scope of the invention. The relation betweenthe field-magnet core and its winding should be such, however, that theformer is maintained at the point of saturation or approximately at thatpoint at all times during the operation of the system. In case themachine 1 is an alternating-current generator a series field-magnetwinding for the motor 9 would probably be most desirable; but for adirect-current system a shunt or a separately-excited winding would bemore desirable for this motor.

The armature of the motor 9 is mechanically connected to the armature ofa small generator 11. This connection may be made by means of belt andpulleys, by mounting the two armatures upon a single shaft, orby eithera flexible or rigid coupling between the shafts of the two machines, allof these means being well known in the art. In view of the greatersimplicity it will probably be advisable to couple the armaturesdirectly and rigidly instead of by means of a belt and pulleys. Thegenerator 11 is shown as provided with a shunt fieldmagnet winding 12,in the circuit of which is a variable resistance, this resistance beingprimarily adjusted to secure the results desired, but is not intended tobe adjusted during the operation of the machine, the reg ulating eifectbeing secured automatically. A series field-magnet winding may also beemployed in connection with the shunt-winding, if desired; but thelatter will probably be found sufficient in all or most cases. Therelation between the winding and its core is such that in normaloperation the magnetic condition of the latter is much below saturation.The armature of the generator 11 is connected in series with theshunt-winding 3 of the generator 1, and the motor 9 is so connected anddriven that the electromotive force impressed by the generator 11 uponthe shuntcircuit of the machine 1 is in opposition to that impressedupon such circuit by the last named generator. If a separately-excitedmain generator be employed, the armature of generator 11 maybe connectedin series with the field-magnet winding of generator 1 and its exciter,so as to act in opposition to the latter. Since the line electromotiveforce is adjusted by adjusting the excitation of the fieldmagnet ofgenerator 1, this adjustment of excitation or magnetization may beeffected by providing a separate opposition winding for the opposingelectromotive force supplied by the generator 1.1 instead of opposingthe normal electromotive force directly in the same winding, as will bereadily understood.

It will be understood from the foregoing description in connection withthe drawings that on account of the saturated field of the mo tor 9 themotor will respond immediately to any change in the electromotive forceof the circuit 5 6, whether due to a-change in speed of the generator 1or to any other cause. The change in speed of the motor 9, due to such.change in electromotive force, effects a corresponding change in thespeed. of the armature of generator 11, and since the field of thelatter is working below saturation a change in its speed will instantlyeffect a change in its field magnet magnetization, and consequently achange in the electromotive force impressed by it upon the field-magnetcircuit of generator 1, with which it is connected. If the variableresistances 4 and 13 have been properly adjusted, this opposingelectromotive force supplied by generator 11 will bear such a relationto the magnetizing electromotive force otherwise applied to thefieldmagnet of the generator 1 that the line electromotive force will bekept approximately constant. This regulation will probably not be soclose as to absolutely eliminate all fluctuations; but the percentage ofincrease and decrease may be made so small as to be unimportant so faras the operation of the translating devices is concerned.

In Fig. 2 I have shown an alternating-current generator 1, havingafield-magnet winding 2, supplied with direct current by a suitableexciter 1a. The motor 9 has a series field-magnet winding 10 and isconnected across the main circuit 5 6, which supplies translatingdevices 7. The generator 11 is constructed to operate the same asgenerator 11, (shown in Fig. 1,) but has its armature electricallyconnected to a winding 15 on the field-magnet of generator 1, so as tooppose the action of the winding 2. The mode of operation and result aresubstantially the same as in the system shown in Fig. 1.

I claim as my invention- 1. Means for regulating the electromotive forceof a circuit supplied by a generator which tends to give a variableelectromotive force, comprising a motor driven by current from saidcircuit and a compensating generator having a shunt-wound field-magnetand having its armature mechanically connected to the armature of saidmotor and electrically connected to a field-magnet winding of the maingenerator so as to exert a magnetizing effect in opposition to thatexerted by the nor* mal maguetizing-current.

2. Means for regulating the electromotive force of a circuit supplied bya variable-speed generator comprising a motor driven by cur rent fromsaid circuit, and a compensating generator having a field magnetprovided with a shunt-winding and having its arma= ture mechanicallyconnected to the armature of said motor and electrically connected inseries with a magnetizing-circuit for the main generator so as to opposethe electromotive force otherwise impressed upon such magnetizing-circuit.

3. In a system of electrical distribution, the combination with a maingenerator which tends to give a variable electromotive force and acompensating generator having ashuntwound field-magnet worked belowmagnetic saturation and an armature electrically connected to afield-magnet winding of the main generator, of a motor driven by currentderived from the main circuit and having a saturated field-magnet and anarmature mechanically connected to the compensating generator so as todrive the same in opposition to the main generator.

4. In a system of direct-current electrical distribution, thecombination with a compound-wound generator, of a shunt-woundcompensating generator having a normallyunsaturated field-magnet andhaving its armature connected to a field-magnet winding .magnet andhaving its armature connected in series with the shunt-winding of themain generator, and a motor driven by current derived from the maincircuit and mechanically connected to the compensating generator so thatthe current supplied by the latter to the shunt-winding of the maingenerator shall oppose its normal current, the field-magnet of saidmotor being normally saturated.

In testimony whereof I have hereunto subscribed my name this 5th day ofOctober, 1898.

BENJ. G. LAMME.

Witnesses:

WESLEY G. CARR, H. O. TENER.

